3800sc swap ECM tune (Page 1/1)
SpunkChicken JUL 21, 11:09 AM
I am almost finished rebuilding my 1985 GT. I have done the 3800SC swap and everything seems to be working well (except a code for a MAF error).

I am looking to tune my ECM and have purchased/downloaded TOAD Pro. And now I realize I need an interface to communicate between the computer and the car. does anyone know of any tuners that will work that will not mean completely starting over?

This is for adjusting the tune, not just scanning for error codes, which I can already do.

thanks!
Dennis LaGrua JUL 28, 06:21 PM
The 3800SC PCM's need several changes to work effectively in a Fiero. Most PCM program editors come with an interface box and cable to attach to your laptop. We use the HP Tuner suite that has both an editor and scanner. The interface boxes that come with tuning programs are usually unique to the particular program. Don't believe all generic boxes would work. I would ask the company that your purchased the tuner program from what they recommend.
Looking at the TOAD site it appears that the program uses an ELM 327 OBD2 adapter. You will need the right version.
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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

[This message has been edited by Dennis LaGrua (edited 07-28-2025).]

olejoedad JUL 28, 06:51 PM
You should have saved your money and sent your PCM to Ryan Gick at Sinister Performance.
fieroguru JUL 28, 06:51 PM
https://www.totalcardiagnostics.com/toad/

Seems like their website was written for an infomercial.

Just an FYI, the data scanning and ability to easily apply the needed changes to the editor is just as important, if not more important, than the actual editor.

While HP Tuners uses separate softwares for both, they are setup for eazy copy/paste between the two. Scanner builds the histogram of needed changes, then you can copy and paste (and paste by 50%) into the editor. Takes about as long as it took to rear this post.

Haltech editor has built in hystograms and simple click of 1 button applies them to the base table (but does not have a paste by 50%).
Dennis LaGrua JUL 29, 04:12 AM
Regularly use HP Tuners but never used TOAD. Its comparing a $100 editing.tuning setup to a $700 package. You already have the $77 software so I would say buy the plug in ELM327 Wired OBD 2 adapter and try it out. They go for about $20 and the wired one should minimize possible interference. The first step in tuning would be to shut off the VATs. Does TOAD do this? If TOAD works as expected I would like to know.

------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

SpunkChicken JUL 29, 03:52 PM
Thanks to most of you for responding. I have decided to bite the bullet and switch to HP tuners. Seems more intuitive. Plus I can play around with the tune for a custom tune, not some generic mail order version.
Dennis LaGrua JUL 29, 04:06 PM

quote
Originally posted by SpunkChicken:

Thanks to most of you for responding. I have decided to bite the bullet and switch to HP tuners. Seems more intuitive. Plus I can play around with the tune for a custom tune, not some generic mail order version.



Yes HP Tuning suite is rather expensive but very versatile and easy to use. My installs would not be working without the tuner and the scanner is without equal. Had to adjust for an LS1 MAF and a N* throttle body and its now dialed in perfectly. The scanner will tell you exactly how everything works together.
The starting point is to disable the VATS. If you wish can give you the procedure.

------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

SpunkChicken JUL 29, 04:54 PM
That would be fantastic. Yes please.
Dennis LaGrua JUL 29, 10:03 PM

quote
Originally posted by SpunkChicken:

That would be fantastic. Yes please.


Not a tuning expert but would be happy to provide some tips for your tune. First we disable the VATS and remove the OBD codes related to items that the car will not use. If you use a different MAF sensor and TB then fueling adjustments need to be made. The MAF table determines the main fueling for the engine on the 3800 PCM. . The other fueling tables are there only for default if the MAF fails. I would recommend not altering the timing tables. IMO adding more advance can be risky. Once you buy the editor and get into it OBD2 tuning is not hard. I find it much easier then OBD 1 tuning.


------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

[This message has been edited by Dennis LaGrua (edited 07-29-2025).]

olejoedad JUL 30, 12:39 PM
SpunkChicken, you have a PM.